Anesthesia management Archives - Page 5 of 20 - Xenon Health

The management of the difficult airway is a topic both ubiquitous and enigmatic in the realm of clinical anesthesia care. Like the famous Justice Stewart quote, you know it when you see it, but no one has a hard and fast definition of what it is. Commonly it’s characterized as a clinical situation in which a conventionally trained anesthesiologist has difficulty with mask ventilation, intubation, or both. How each practitioner chooses to approach such situations, both expected and unexpected, varies based on whom you ask. Even among the world’s airway experts there are patterns of agreement, but no clear rules on how to handle airway management.

The first step of difficult airway management is recognition and preparation. Red flags in the patient’s history (previous difficult mask/intubation, obstructive sleep apnea, head and neck radiation, mediastinal mass, ankylosing spondylitis to name a few) and physical exam (table below) should be reviewed whenever possible and adequate preparation made for cannot ventilate/cannot intubate scenarios.

Informing the patient of possible difficulties involving airway management, having an extra pair of hands if possible, ensuring adequate preoxygenation, and actively pursuing avenues to continue delivering supplemental oxygen for the duration of airway management (via nasal cannula, LMA, insufflation, etc) are part of the basic preparation recommended by the ASA. Choosing appropriate avenues to secure the airway is based upon provider familiarity and specific patient circumstance, and includes but is not limited to video laryngoscopy, fiberoptic intubation, and light wand. Perhaps more important than how to intubate the patient is to decide whether to perform intubation after induction or awake. Choosing the former without convincing evidence of the ability to mask ventilate would be difficult to defend should adverse consequences occur.

In spite of adequate preoperative assessment, unanticipated difficult airways are still encountered and can have devastating consequences. Reference to the difficult airway algorithm below is helpful in systematically attempting to establish adequate ventilation and/or intubation.

References:

Apfelbaum, JL et al.  Practice Guidelines for Management of the Difficult Airway: An Updated Report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 02 2013, Vol.118, 251-270.

Providing safe and effective anesthesia services is a full day’s work.  The physician anesthesiologist must thoroughly review each patient’s medical history and come up with an anesthesia plan that not only considers patient safety but also the surgeon’s preferences.  Oftentimes, this is achieved by speaking directly with the patient and the surgeon, whether it be in person or over the phone, the day before the surgery.

The morning of, the physician anesthesiologist is often the first person to arrive in the operating room.  Like a pilot preparing for a flight, the anesthesiologist must embark on a systematic checklist to ensure that all equipment is functioning properly and all supplies including emergency supplies are stocked and available in the room.  The anesthesia machine is checked, the suction catheter is on and readily accessible, all monitors are available and ready to connect to the patient, airway equipment is selected for the patient and double checked for leaks or malfunction, intravenous access kits and fluids are set up, and medications are drawn up with doses already calculated.

Once the anesthesia station in the operating room is ready to go, the physician anesthesiologist then meets the patient in the preoperative area to clarify his or her medical history, assuage any fears or concerns the patient may have, and discuss the benefits and risks of the anesthesia plan.  A focused review of systems and physical exam is performed, with special attention to the cardiopulmonary systems and airway exam.

The patient is then transported to the operating room.  Once monitors are in place, the anesthesiologist preoxygenates the patient and induces anesthesia.  After the patient is asleep, he or she is intubated.  If a difficult airway is encountered, additional equipment such as a Glidescope or fiberoptic scope may be utilized.  The anesthesiologist then monitors the patient closely during the surgery and, once the surgery is done, the patient is emerged and extubated before being transported to the recovery room.  If needed, the patient may remain intubated and go to the ICU.

The anesthesiologist’s responsibilities do not end there.  The patient must be carefully monitored as he or she wakes up from the effects of anesthesia.  The physician orders pain and anti-nausea medications as needed and is available if there are airway or hemodynamic concerns during this period.  Once the patient meets discharge criteria, they can return to an inpatient room or go home.  The next day, the anesthesiologist does a postoperative visit or call to address any concerns or questions that the patient had regarding their anesthesia experience.

As discussed in the British Journal of Anaesthesia, the fundamental purpose of healthcare is to achieve good health outcomes for patients (Murphy, 2012). Researchers measure and publish clinical outcomes of healthcare services to ultimately improve their quality and establish a minimum standard of care.  However, collecting data on such performance measurements renders ample costs, specifically pertaining to anesthesia services. Many believe that measuring performance of healthcare providers such as anesthesiologists, CRNAs and others is not feasible due to the large amount of accurate, high quality data that is necessary for national comparisons, the lack of which results in flawed analyses and data misrepresentation. The current incapacity to precisely, collectively capture health outcomes for anesthesia patients in addition to the misuse of data, like misrepresentation, are some examples of the costs of collecting data on healthcare performance measurement. Because individuals are seldom provided the appropriate context to interpret such measures, an information discrepancy in healthcare performance measurement arises, leaving patients unable to determine what information is relevant to their care. This discrepancy, otherwise known as healthcare asymmetry, can adversely affect professional attitudes and patient-doctor relationships.

Because anesthesiologists, CRNAs and other anesthesia service providers provide multifaceted services to complex patients, despite researchers’ ability to collect process data, little information exists on patient health outcomes after the receipt of anesthesia services. One problem with measuring such outcomes is related to the fact that modern anesthesia is relatively safe, thus, mortality is not a sensitive indicator or measure of quality in healthcare performance. Further, no consensus has been established regarding how to measure perioperative anesthesia-related mortality, as its temporal definition ranges from death within 48 hours of an anesthesia procedure, to within 30 days of a procedure, among many others observed in the literature. Researchers must define quality measures needed to understand health outcomes in anesthesia practice to identify areas of need, and ultimately lessen the burdensome costs of healthcare performance measurement in regards to anesthesia services. While the healthcare system should promote accountability and transparency, efficient data collection should accurately reflect performance of anesthesiologists, CRNAs and other anesthesia services professionals, and be distributed to consumers as it is deemed relevant to understanding their care. To overcome such costs of healthcare performance measurement for anesthesiologists, CRNAs and others involved in providing anesthesia services, measures must be defined, identified and agreed upon, so as to assure consistency in national data collection, in order to determine the most efficient and effective means of care in terms of cost, risk and health outcomes for patients undergoing anesthesia services.

Heart rate variability (HRV) is a parameter not often heard about in clinical practice, yet it has been studied for over a decade as a marker for autonomic nervous system function. Heart rate varies with respiration, a physiologic process controlled by autonomic reflexes and central autonomic input. A decrease in this physiologic variation in heart rate has been associated with impairment in the cardiovascular system’s ability to adapt to various stressors. Abnormalities in HRV have been observed in various populations and pathologies in which the autonomic nervous system has been compromised, and in many cases (such as after acute coronary syndrome or in critically ill neurosurgery patients) can predict mortality and adverse outcomes.

Measurement of HRV is commonly done via time domain analysis and frequency domain analysis of R-R intervals on EKG. Parameters calculated from these spectral analyses infer the functionality of the sympathetic and parasympathetic nervous systems.

Intellewave is an automated cardiac monitoring device that utilizes frequency domain analysis to provide real-time quantitative assessment of HRV. It uses novel artificial intelligence techniques to differentiate between high frequency (HF) and low frequency (LF) components of this spectral analysis. The HF band reflects parasympathetic activity and the LF band represents mixed input from both sympathetic and parasympathetic modulation. Interpretation of the spectral parameters has yet to be well-defined, but is the subject of ongoing study in various populations.

Intellewave’s Nerve Express algorithm was compared to the gold standard CHRONOS algorithms for power spectral analysis of R-R intervals, the latter of which was shown to predict mortality in coronary disease and to quantify physical fitness in athletes. Its advantage over CHRONOS, which relied on Holter monitoring and required skilled technicians, was designed to be a stand-alone automated system that could be used in an office setting.

The applications for HRV in general and Intellewave in particular within the perioperative theater have yet to be closely examined. From pre-operative risk stratification of patients at risk for intraoperative complications due to autonomic dysfunction, to postoperative monitoring and predicting outcomes in an intensive care setting, the possibilities are broad. There exist however confounding factors to the utilization of HRV in practice, for in the very breadth of its potential applications lies its weakness: the autonomic system affects so many variables and is affected by so many pathologies, medications, and stressors that it would be difficult to tease out what exactly is causing a change in HRV and what it could be predicting. Nevertheless, it remains an intriguing forefront of research.

Anesthesiologists commonly perform spinal blocks for a multitude of procedures, including lower body surgeries involving the genitourinary tract, orthopedic surgeries like knee replacements, lower abdominal surgeries, and cesarean sections. Spinal anesthesia involves the single injection of medication into the intrathecal space — into the fluid surrounding the spinal cord — to cause complete numbness and analgesia from the waist down.  The onset of anesthesia is only a few minutes, and the effects can last up to a couple of hours before wearing off without further intervention.  Spinal anesthesia is often supplemented with light or moderate sedation for patient comfort, though a spinal block alone is sufficient anesthesia for an operation.  Spinal blocks offer reliable and rapid onset anesthesia and are a safe and effective alternative to general anesthesia.

The technique for administering spinal anesthetics involves palpating for landmarks and identifying an appropriate space along the vertebral column, usually the L3-L4 or L4-L5 intervertebral spaces at the midline.  Once identified, the skin is numbed with local anesthetic, and then the spinal needle is inserted via an introducer needle.  When cerebrospinal fluid is aspirated to confirm correct positioning, the medication is injected, the needle is removed, and the procedure is complete.

According to startup company IntuiTap Medical, this current technique is “highly unpredictable and requires significant guesswork.”  This can be even more pronounced when the bony landmarks are difficult to palpate, such as in obese patients or patients with scoliosis or history of spinal surgeries.  As a result, multiple attempts may be necessary to correctly identify the intrathecal space, resulting in a distressing experience for the patient and physician, as well as increased risk of post-dural puncture headaches.  These complications can increase risk of readmission and threaten patient satisfaction.

IntuiTap has created a handheld device that integrates imaging of the spine with needle guidance and analytics to increase first-pass success.  The device enhances palpation by showing a real-time image of the underlying vertebrae on a handheld LCD screen and projecting, using a proprietary algorithm, exactly where the needle will end up if inserted at that location.  A digital pressure sensor confirms positioning of the needle and measures opening pressure, obviating the need for a separate and cumbersome manometer.

The company was co-founded by its CEO Jessica Traver and CTO Nicole Moskowitz, both of whom were featured in Forbes annual list of 30 under 30 for healthcare.  Over the past year, IntuiTap has started seed funding rounds and has been awarded space at Johnson & Johnson Innovation’s JLABS and taken part in TMCx and MedTech Innovator accelerator programs.